Railway-traffic-controlling apparatus



Oct. 2 9, 1929. A. A, SKENE RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Jan. 30, 1928 2 Sheets-Sheet M MI INVENTOR BaPhS/(enc,

N .I It N 3 R Oct. 29, 1929.

A. A. SKENE RAILWAY TRAFFIC CONTROLLING APPARATUS 2 Sheets-Sheet 2 Wm 1 13? EYE 1 WL R A A mm 3 A N mm 9n N w H. MW M w .E 7 @MW H l N 5N v N 3 .u, w

Filed Jan. 30, 1.928

Patented Oct. 29, 1929 UNITED STATES PATENT OFFICE ANDREW A. SKENE, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOB TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION 01 PENNSYLVANIA RAILWAY-TRAITIC-CONTROLLING APPARATUS Application filed Ianuary30, 1928. Serial No. 250,402.

My invention relates to railway trafiic controlling apparatus, and particularly to apparatus of the type comprising train carried governing means controlled by energy received from the trackway.

I will describe several forms of railway traffic controlling apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view illustrating one form of railway trafiic controlling apparatus embodying my invention. Fig. 2 is a View show ing a modified form of a portion 'of the apparatus illustrated in Fig. 1 and also embodying my invention. Figs. 3, 4 and 5, are views showing still other modifications of the apparatus shown in Fig. 1 and also embodying my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the reference characters 1 and 1 designate the track rails of a stretch of railway track over which traflic normally moves in the direction indicated by the arrow. These rails are divided, by means of insulated joints 2, into a plurality of successive track sections only one of which A-B, is shown complete in the drawing. Train controlling current is supplied to the rails of this section from a suitable source of energy such as an alternator G. The current supplied to the trackway by this alternator may be of a frequency of the order of the usual commercial alternating current such for example as cycles or 100 cycles per second.

The supply of current to the track rails is controlled by a coding device designated in general by the reference character X and comprising a plurality of rotatable cams each designated by the reference character C with a suitable distinguishing exponent. The cams C are driven at a constant speed by a suitable motor M which is supplied with current from the alternator G. C is provided with a plurality of swells 8 spaced about its periphery and which swells successively engage a contact 3 to periodically ,close the contact as the cam C is ro The cam tated. In similar, manner the cams C and C are provided with difierent numbers of swells 8 which control contacts 4 and 5, respectively. One terminal of the alternator G is constantly connected with rail 1 of section A B, and the other terminal of the alternator is connected with the rail 1 through one of the contacts 3, 4 or 5, depending upon traffic conditions.

It is manifest that the alternating current supplied to the rails of the trackway by alternator G is periodically varied at the frequency of operation of the contact of the device X that is interposed between the alternator and the track rail 1. The coding device X may be constructed to cause such variations at any reasonable frequencies, but for purposes of illustration, I will assume that the cams C are rotating at 20 revolutions per minute, that cam C has 4 swells, that cam C has 6 swells and that cam C has 9 swells. The selection between the several contacts of the coding device X in accordance with tratlic conditions may be accomplished in any suitable manner, such, for example, as by means of a home relay H and a distant relay L. The circuits for controlling these two relays form no part of my present invention and are omitted from the drawing for the sake of simplicity. For present purposes it is sufficient. to state that home relay H is normally energized but is de-energized when a train occupies the section immediately to the right of point B. The distant relay L is also normally energized but is de-energized when a train occupies either the first or the second section immediately to the right of point B. \Vith the apparatus thus far described, when relays H and L are both energized so that front contact 66 of delay H and front contact 7---7 of relay L are closed, current from alternator G, which current I will assume to be of 100 cycles per second, is supplied to the track rails over contact 5 operated by cam C Under these conditions, the alternating current supplied to the trackway is periodically varied at a frequency of 180 cycles per minute. Current supplied to the trackway undcr these condtions. I will hereinafter term the proceed code. lVhen relay H is energized and relay L is de-energized, the closing of back contact 7-7 of relay L includes contact'4 controlled by cam C in the trackway circuit, and under these conditions the trackway is supplied with 100 cycle current interrupted at a frequency of 120' cycles per minute; this current I shall hereinafter term the caution code. In similar manner, when relay H is dq-encrgized, the closing of back contact 66 of this relay completes a circuit from alternator G to the track rails through contact 3 operated by cam C Under these conditions, the trackway is supplied with 100 cycle current interrupted at a frequency of 80 cycles per minute, which current I will call the slow code.

The train indicated diagrammatically at V is provided with governing means which is responsive to the frequency of the periodic variations in the 100 cycle current supplied to the trackway. In the present embodiment of my invention the train is provided with two magnetizable cores 11 and 11 located in advance of the forward axle 10 and disposed in inductive relation to the two track rails 1 and 1, respectively. Core 11 is provided with a winding 12, and core 11 is provided with a winding 12*, the two windings 12 and 12 being connected in series in such manner that the voltages induced therein by train controlling current flowing in opposite directions in the track rails at any instant are additive.

The voltages induced in windings 12 and 12" control a device R which operates as a relay. This device comprises an electron emitting member which in the form here shown is a filament 27 which is heated by current from a suitable source of energy, such as a battery 28, connected with the filament through a resistance 29. The relay R also comprises a thermo-sensitive element 15 which, as shown in Fig. 1, is a bi-metallic strip arranged to swing into engagement with contact 15 when the strip is relatively cool and to swing into engagement with contact 15 when the strip is relatively warm. Tindings 12 and 12 are connected with a grid 30 and the filament 27 so that the energization of the grid varies in accordance with variations in the voltages induced in the windings 12 and 12 Battery 31, having one terminal connected with filament 27 through resistance 29 and having the other terminal connected with the thermo-sensitive element 15, creates a diff rence of electrical potential between the filament 27 and the element 15. It will be plain, therefore, that due to this dif ference in potential electrons emitted by the filament 27 are caused to bombard the element 15 and that this bombardment is controlled by the potential of the grid 30 which is in turn controlled by the train controlling current supplied to the track rails. The parts are so adjusted that the variation in bombardment of the element 15 due to variations in the train controlling current caused by the coding device X is suflicient to change the temperature of the element 15 enough to swing it alternately into engagement with contacts 15 and 15 Vhen the current in the track rails is being periodically varied, therefore, the element 15 swings alternately into engagement with contacts 15 and 15 at the frequency of the variations in the trackway current.

Associated with relay R is a transformer T comprising a primary 16 anda secondary 17. Direct current is supplied to the primary 16 of transformer T from a suitable source of energy such as a battery D, and the supply of such current is periodically varied in accordance with the frequency at which the temperature of the thermo-sensitive element 15 is varied. As shown in the drawing, when contact 15--15 is closed, cur rent flows from battery D, through the upper half of primary 16 in one direction, but when contact 1515 is closed, current flows from battery D, through the lower half of primary 16 in the opposite direction. It follows that when the trackway current is being periodically varied, the current in primary 16 of transformer T is periodically reversed and re-esta-blished in the original direction at the same frequency as the periodic variations in the trackway current.

As a result of this periodic current in the primary of transformer T there is induced in the secondary 17 an alternating electromotive force of a corresponding frequency, which electromotive force is applied to a plurality of circuits each designated by the reference character F with a distinguishing exponent, and each comprising a reactor 18 and a condenser 19 by means of which the several circuits are tuned respectively to the frequencies of the variations in the train controlling current. Thus circuit F is tuned to resonance at the frequency of the interruptions in the proceed code, or 180 cycles per minute. A relay K is connected across a portion of reactor 18 of circuit F through a rectifier J. In similar manner, circuit F is tuned to resonance at 120 cycles per minute and relay K is connected across a portion of reactor 18 of this circuit through a rectifier J Relay K is connected, through rectifier J with a portion of reactor 18 of circuit F which circuit is resonant at 80 cycles per minute.

In explaining the operation of the apparatus as a whole, I will first assume that the proceed code is being supplied to the trackway so that the trackway current is being varied at a frequency of 180 cycles per minute. Relay R therefore operates to reverse the current in primary 16 of transformer T at a rate of 180 cycles per minute and alternating current of a corresponding frequency is supplied to each of the circuits F. At this frequency circuits F and F are detuned so that the electromotive forces across those portions of reactors 18 of these circuits to which the corresponding relays K are connected are comparatively small. Circnit F is tuned to resonance at this frequency and the resonant rise of electromotive force in reactor 18 of circuit F is com aratively large. A comparatively large electromotive force is therefore applied to rectifier J resulting .in a comparatively large current in the relay K Relay K is adjusted to become ener ized when current of this magnitude is supplied to the relay. When the train is receiving the proceed code, therefore, relay K is energized, but relays K and K are deenergized. Under these conditions, current from battery D flows over front contact 2424 of relay K to light lamp 20, thereby displaying a proceed indication.

I will now assume that the caution code I is being supplied to the trackway so that relay It operates element 15 at a frequency of 120 cycles per minute. Alternating current of a corresponding frequency is therefore supplied tothe circuits F by secondary 17 of transformer T. Under these conditions, the current supplied to relays K and K is not sufficient to energize the relays but due to the tuning efiect of'circuit F which circuit is resonant at 120 cycles per minute, there is a comparatively high resonant electro-motive force in reactor 18 of circuit F As a result, sufiicient current is supplied to rela K to energize this relay. Under these con itions, relay K is closed and relays K and K are open, and current from battery D flows over back contact 21-24: of relay K and front contact 25-25 of relay K to lamp 21, thereby lighting this lamp to indicate caution.

In similar manner, when the slow code being supplied to the trackway, relays K and K are both de-energized, but circuit F is tuned to resonance at the frequency of the current now supplied by secondary 17 of transformer T so that relay K is energized and current from battery D flows over back contact 249-24 of relay K back contact 25-25" of relay K and front contact 2626 of relay K to lamp 22. Lamp 22 is therefore lighted to indicate slow.

If section A-B were occupied by a second train located between train V and point B, train controlling current would be shunted away from train V by the wheels and axles of such second train. As a result, relay It would be .continuously de-energized. If, for.

this reason, or for any other reason,'relay R should fail to operate its contacts 15 and 15 intermittently, the supply of energy to all therelays K would be discontinued and these relays would be open. Current would then flow from battery D, over back contact 21-24:" of rela K, back contact 2525 of relay K and ack contact 2626 of relay K, to lamp 23, thereby lighting this lamp to display a stop indication.

For purposes of explanation, I have described the relays K as controlling only the lamps 20, 21, 22 and 23, but it should be understood that these relays may control train governin means of any suitable type not shown in t e drawing.

I have disclosedapparatus which sup lies only three codes to the trackway and ave shown train carried governing means adapt ed to distinguish only between these three codes. It should be understood, however, that my invention is not limited to this number of codes but that the equipment could be expanded to provide additional code frequencies and additional tuned circuits on the train to select between such frequencies.

Referring now to Fig. 2, the relay R is constructed as has already been described in connection with Fig. 1 and the receiver windings 12 and 12 are connected with the grid 30 and filament 27 of this relay. A resistance 32 is inserted in the grid circuit, however, for a urpose which will be explained hereina ter. The battery 31 has one terminal connected with filament 27 through resistance 29'asin Fig. 1, but the other terminal: of this battery is connected with the element 15, through the primary 33 of a transformer P. The secondary 31 of transformer is connected, through a full-wave rectifier'35 and a filter W, across the terminals of the resistance 32 in the grid circuit of the relay R. It follows, therefore, that when animpulse of energy is impressed upon the gid iiicircuit of the relay R, this impulse causes a variation in the intensity of the electron stream bombarding the element 15. As a result, the intensity of the current flowing through the primary 33 of transformer P is also varied. This variation induces in secondary 34 of transformer P, an electromotive force which is rectified and applied'across the terminals of resistance 32. The potential difference thus supplied to the terminals of resistance 32 causes a change in the potential ofthe grid 30 with respect to the filament 27 and the parts are so proportioned that this change in grid potential has a tendency to vary the bombardment of the strip 15 in v the same direction as the impulse which- 2 will, therefore be understood without further explanation.

It should be pointed out, however, that with the a paratus illustrated in Fig. 2, due

to the re exing action of the circuits, the

impulses delivered by the receiver windings 12 and 12 are materially amplified so that the variations in the temperature of the strip 15 are more pronounced, than with the apparatus shown in F ig. 1.

An alternate form of relay device is illustrated in Fig. 3 and designated by the reference character R This device comprises an electron emitting member 1n the form of a filament 36 heated by current from t a battery 38. Surrounding the filament 36 is a thermo-sensitive element 37 here shown as a cylinder of material having a high temperature coefficient of resistance. The element 37 is a part of a circuit which includes also a battery D and the primary of a transformer T the secondary of which may supply alternating current to tuned circuits F which are separately responsive to the frequencies of such currents as in Fig. 1. The receiver windings 12 and 12 are connected through a suitable amplifier 18 with the primary of a transformer Q, the secondary of which is connected between the filament 36 and the thermo-sensitive element 37. The.voltage induced in windings 12 and 12* by the trackway current therefore causes a difference of'potential between the filament 36 and the element 37 of the relay R During each imulse of such current, the potential difference etween the filament 36 and the element 37 Will have one value which is different from the value of this potential difference during the intervals between successive impulses of the current supplied to the trackway. It follows therefore that the intensity of the electron stream bombarding the thermo-sensitive element 37 will be varied at the frequency of the variations in the trackway current. The temperature of the thermo-sensitive element 37 will be correspondingly varied .and the current supplied to the primary of'transformer T will be varied at the same freuency. It should be noted that in Fig. 3 the direction of the current in the primary of transformer T is never reversed but is only changed between a maximum and a minimum, but this change results in the creation,

in the secondary transformer T of an alter: nating current which may be utilized to selectively energize the tuned circuits F and their corresponding relays K, as in Figs. 1

.and 2.

tial of the grid. The receiver windings 12 in accordance with variations in the and 12" are connected across the grid 39 and filament 36 so that the grid potential is varied trackwa'y current. The battery 40 creates an electrical potential difference between the element 37 and the filament 36, and the element is therefore heated by bombardment of a stream of electrons, the intensity of which varies in accordance with the variations in the trackway current and causes variations in the current supplied to the primary of transformer T.

In each of the modifications here shown and described it should be pointed out that the relay device R or R comprises a thermo-sensitive element which is heated by bombardment of an electron stream, the intensity of which varies in accordance with variations in the trackway current, and that the relay device operates independently of the frequency of the trackway current itself, but responds only to variations in the magnitude of this current.

In the modified form of apparatus shown in Fig. 5, the reference characters R and R designate relay devices each comprising a heater 42 and an element 43 of thermo-sensitive material, that is, materiahhaving' a high temperature coefficient of resistance. Each element 43 is subjected to changes in the temperature of the associated heater 42. The heater 42 of device R is connected with the secondary of transformer Q, the primary of which is supplied with energy from the receiver windings 12 and 12. A filter 47 may be interposed between the receiver windings and the transformer to suppresscurrents of undesired frequencies. A battery D supplies current to heater 42 of device R in series with element 43 of device R and a battery D supplies current to the primary of transformer T in series with element 43 of device R With the apparatus here shown, when train controlling current is being supplied to the trackway, each impulse of such current increases the temperature of heater 42 of device R This causes a change in the temperature, and hence in the resistance, of element 43 of device R As a result, the current through heater 42 of device R is varied. and the consequent change in the resistance of element 43 of device R varies the current in the primary or transformer T It will be plain, then, that variations in the trackway current cause variations in the current in the primary of transformer T, which induce an alternating electromotive force in the secondary of this transformer. The tranformer T may be used to supply energy to governing means selectively responsive to the frequency of the current supplied thereto, as in Fig. 1.

With relay devices of the type here illustrated, the variation in the current through the element 43 of a device may be many times the variation in the heater current which causes it, so that a considerable degree of amplification may be obtained by each such device.

It should be pointed out that the amplifier 13 shown in Fig. 3 could be interposed between the receiver windings 12 and 12 and the relay R in Figs. 1 or 2, or between the receiver windings 12 and 12 and the relay R in Fig. 4, or between the receiver windings and relay R in Fig. 5. Furthermore, the reflex circuit shown inzaFig. 2 could be utilized with the relay R shown in Fig. 4.

Although I have herein shown and described only a few forms of railway traffic controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein Within the scope of the appended claims without departing from the spirit and scope of my invention. I

Having thus described my invention, what I claim is:

1. Railway traffic controlling apparatus comprising an electron emitting member, a thermo-sensitive element heated by bombardment due to emission of electrons from said member, train controlled means for at times Varying the bombardment of said element at different frequencies, and traific, governing means responsive to the frequency of varia tions in the temperature of said element.

2. Railway trafiic controlling apparatus comprising a train carried electron emitting member, a thermo-sensitive element heated by bombardment due to emission of electrons from said member, means located partly in the trackway for at times varying the bombardment of said element at different frequencies, and train carried governing means selectively responsive to the frequency of variations in the temperature of said element.

3. Railway traflic controlling apparatus comprising a train carried electron emitting member, a thermo-sensitive element heated by bombardment due to emission of electrons from said member, means located partly in the trackway for at times varying the bombardment of said element at diflerent frequencies, a plurality of circuits each tuned to resonance at one of such different free quenoies, means for supplying said circuits with current of the frequency of variations in the temperature of said element, and governing means selectively controlled by said circuits.

f. Railway trafiic controlling apparatus comprising means for supplying alternatingcurrent to the trackway, means for periodically varying said current at different fre-,

quencies, a train carried electron emitting member, a thermo-sensitive element heated by bombardment due to emission of electrons from said member, means for governing the bombardment of said element in accordance with the variations in the trackway current, and train carried governing means selectively responsive to the frequency of variations in the temperature of said element.

5. Railway traffic controlling apparatus comprising means for supplying alternating current to the trackway, means for periodically varying said current at different frequencies, a train carried thermo-sensitive element, means for heating said element, means from said member, means controlled from the trackway for governing the bombard ment of said element, means responsive to the temperature of said element for governing the bombardment of the element, and governing means on the train controlled in accordance with the temperature of said element.

7. Railway trafiic controlling apparatus comprising means for supplying alternating current to the trackway, means for periodically varying said current at diiferent frequencies, a train carried electron emitting member, a thermo-sensitive element heated by bombardment due to emission of electrons from said member, a grid for governing the bombardment of said element, means responsive to the variations in the trackway current for governing the energization of said grid, means responsive to variations in the temperature of said element to vary the energization of said grid, and train carried governing means selectively responsive to the frequency of variations in the temperature of said element.

In testimony whereof I aflix my signature.

ANDREW A. SKENE. 

